Thin films have been in use for well over a thousand years. Among the earliest uses were decorative thin films on glass and ceramics. From the early examples have evolved the diverse types of thin films currently used. Included are thin films used for protective and insulating purposes, as well as the conductive thin films used in micro-electronics.
Desirable properties of thin films include uniform thickness and an absence of voids. Spin coating is a well recognized method to uniformly distribute thin film across the surface of a substrate. The coating is applied to the substrate, and then the substrate is rotated rapidly about an axis parallel to the plane of the substrate. One of the most problematic areas associated with the spin coating method is in holding the substrate for the application of the coating and the subsequent spinning operation. Prior art techniques of holding the substrate for spin coating have included manual clamps that are engaged by the operator, and mechanically actuated clamps. These techniques require the step of the operator engaging the clamp. The clamps may potentially damage the substrate, and the mechanical actuators are subject to breakdown. Other prior art techniques have included vacuum fixtures. However, the use of vacuum fixtures is undesirable in that the vacuum ports thereof tend to draw in the coating material.
Although the spin coating fixtures of the prior art fixtures have proven generally suitable for their intended purposes, they possess inherent deficiencies which detract from their overall effectiveness and desirability. In view of the shortcomings of the prior art, it is desirable to provide a spin coating fixture that does not require the operator to engage tooling pins to hold the substrate. It is further desirable to provide a spin coating fixture that does not require mechanical actuators or vacuum ports.